1. Field
One embodiment of the invention relates to improvements of a picture signal processor and a picture signal processing method, the processor performing an amplitude correction processing to a color signal in accordance with the a change amount of a luminance signal by means of a non-linear correction processing.
2. Description of the Related Art
As is already known, flat panel-type large-screen displays have been developed in recent years, and have been put to practical use in color television broadcast receivers and the like. Then, in this kind of large-screen displays, a non-linear correction processing is performed to a luminance component of a picture signal in order to allow a display image to be clearly displayed, so that an amplitude level of the color signal is corrected in accordance with a ratio in amplitude level between the luminance signals before and after the non-linear correction processing.
However, in the amplitude correction processing with respect to the color signal, no particular disadvantage is detected in the case where the non-linear correction processing is performed in a direction in which, for example, an amplitude level of a luminance signal is heightened. On the other hand, in the case where the non-linear correction processing is performed in a direction in which the amplitude level of the luminance signal is lowered, there is shown a phenomenon in which colors are darkened. For example, there is generated a phenomenon in which vividness of images is damaged at the time of displaying, for example, the red color of apples or the like.
For example, Jpn. Pat. Appln. KOKAI No. 2000-115799 discloses a configuration in which a difference between a luminance signal input to a gamma correction circuit and a luminance signal output from the gamma correction circuit is calculated to determine a change amount of the luminance signal by means of gamma correction, so that a color-difference signal is uniformly amplified with a gain corresponding to the change amount to control chroma thereof. Thus, the above-described phenomenon is generated.